A seismic data processing method and system for reducing OVT domain processing scale

Abstract

The present application relates to a kind of seismic data processing method and system for reducing the scale of OVT domain processing, the method includes obtaining seismic data;The seismic data obtained is encrypted by data encryption technology, and certain interval is encrypted to geophone line or shot line, to reduce the scale of OVT domain in the direction of shot line or geophone line, then the seismic data obtained is converted to OVT domain, and OVT slice is divided according to shot line distance and geophone line distance in OVT domain;For any OVT slice, obtain its conjugate OVT slice, carry out coordinate exchange to its conjugate OVT slice, and the conjugate OVT slice after coordinate exchange is superimposed to the OVT slice, the OVT slice after superposition is cut along OVT slice center line and along the direction of geophone line or shot line, to reduce the scale of OVT slice in the direction of geophone line or shot line.In the present application, by cutting processing, the scale of geophone line or shot line direction processing is reduced, so that the problem of large OVT domain processing scale in seismic acquisition data in the prior art can be solved.

Description

Technical Field

[0001] This invention belongs to the field of wide azimuth processing in seismic exploration, specifically relating to a seismic data processing method and system for reducing the processing scale of the OVT domain. Background Technology

[0002] In recent years, with the increasing complexity of seismic exploration targets and the continuous improvement of geological requirements, wide-azimuth high-density seismic exploration technology has gradually become the development direction of seismic exploration. Among them, OVT domain processing technology, as one of the processing methods for wide-azimuth seismic data, has attracted much attention. OVT (Offset Vector Tile) is usually translated as shot-receiver vector tile, also known as common offset vector (COV). The concept of OVT was first proposed by Vermeer when studying the minimum dataset of cross-shaped arrangements. Because OVT gathers have similar offsets and azimuths, OVT gathers are also called common offset and common azimuth gathers. OVT is a subset of data within a cross-shaped arrangement gather. OVT tiles are divided according to the shot distance and receiver distance in each cross arrangement. Each OVT tile consists of shot points within a finite range along the shot line and receiver points within a finite range along the receiver line. OVT has a limited range of offset and azimuth. OVT tiles with the same number are grouped into OVT gathers. This OVT gather is uniform, a single-coverage data volume covering the entire work area, and consists of seismic traces with roughly the same shot-receiver distance and azimuth. Therefore, the OVT gather can be independently pre-stack migrated and imaged, and the azimuth and offset information can be preserved after migration, making it suitable for azimuth analysis. In addition, it has good shot-receiver interchangeability and consistency, and can truly preserve the original data acquisition characteristics. After migration, the energy of near, middle and far traces is consistent, and the amplitude characteristics are good, which is beneficial for inversion.

[0003] While OVT domain processing offers numerous advantages, it places high demands on the original acquired data. Theoretically, each OVT sheet should have similar offsets and azimuths. However, this is based on the assumption that the shot distance and receiver distance are small during field acquisition. Currently, when processing seismic acquisition data, especially reprocessing older data, the original seismic data has larger shot distances and receiver distances, meaning the OVT domain processing scale is larger. This results in a larger range of offsets and azimuths within an OVT sheet, affecting the consistency of offsets and azimuths within an OVT sheet and consequently impacting the final OVT domain processing effect. In patent application CN112630822A, a method and system for pre-stack seismic data processing in the OVT domain are disclosed. This method sorts the original data into OVT gathers with different offsets and azimuths, utilizes the signal correlation within the OVT gathers, and enhances the effective weak reflection signals masked by noise while preserving the phase. This improves the overall signal-to-noise ratio of the pre-stack data, resulting in significant improvements in the pre-stack gather, stacking, and imaging profile effects. However, it did not truly solve the problem of handling large scales in the OVT domain. Summary of the Invention

[0004] This invention provides a seismic data processing method and system for reducing the processing scale in the OVT domain, which solves the problem of large processing scale of seismic acquisition data in the OVT domain in the prior art.

[0005] To address the aforementioned technical problems, this invention provides a seismic data processing method for reducing the processing scale in the OVT domain, comprising: 1) acquiring seismic data; 2) converting the acquired seismic data to the OVT domain, and dividing the OVT into OVT slices according to the shot distance and receiver distance in the OVT domain; 3) for any given OVT slice, acquiring its conjugate OVT slice, performing coordinate interchange on the conjugate OVT slice, and superimposing the coordinate-interchangeable conjugate OVT slice onto the given OVT slice, and cutting the superimposed OVT slice along the centerline of the OVT slice and in the direction of the receiver or shot to reduce the scale of the OVT slice in the direction of the receiver or shot.

[0006] The beneficial effects of the above technical solution are as follows: Seismic data is converted to the OVT domain for OVT sheet partitioning. After partitioning, based on the interchangeability principle of OVT domain data, a cutting method is used to superimpose and cut two conjugate OVT sheets to optimize the OVT sheet. In this case, the seismic data before and after cutting neither increases nor decreases; it simply re-divides the OVT sheet data. This reduces the OVT domain processing scale by half in the receiver or shot direction, ultimately achieving the goal of halving the OVT sheet processing scale. This reduces the range of offset and azimuth within the OVT gather, enhances the consistency of offset and azimuth within the OVT gather, and significantly improves the OVT domain processing effect.

[0007] Furthermore, in order to better reduce the processing scale in the OVT domain, the present invention provides a seismic data processing method for reducing the processing scale in the OVT domain, which further includes, in step 1), encrypting the acquired seismic data at certain intervals using data encryption technology to reduce the scale of the OVT domain in the direction of the shot line or the direction of the receiver line.

[0008] Furthermore, in order to better reduce the processing scale in the OVT domain, the present invention provides a seismic data processing method for reducing the processing scale in the OVT domain, which also includes a data encryption technique of one of five-dimensional interpolation algorithm, trace interpolation, and surface element equalization.

[0009] Furthermore, to better densify receiver or shot lines, this invention provides a seismic data processing method that reduces the processing scale in the OVT domain. This method also includes the five-dimensional interpolation algorithm achieved by solving a minimum objective function, which satisfies the equation: J=║dT·x║ 2 +λ║x║1, where J represents the minimum objective function, d is the actual recorded wave field, T is the sampling operator, x is the ideally fully sampled five-dimensional data volume, λ is the regularization coefficient, λ≥0, and ║x║1 is the L1 norm.

[0010] Furthermore, in order to better densify the detector lines or shot lines, the present invention provides a seismic data processing method for reducing the processing scale of the OVT domain, which also includes selecting the regularization coefficient based on the noise level of the original data.

[0011] Furthermore, in order to better densify the receiver lines or shot lines, the present invention provides a seismic data processing method for reducing the processing scale of the OVT domain, which also includes selecting the regularization coefficient of 5%-30%.

[0012] Furthermore, in order to better densify the detector lines or shot lines, this invention provides a seismic data processing method that reduces the processing scale in the OVT domain. It also includes transforming the seismic data to the frequency-spatial domain using the five-dimensional interpolation algorithm, and then applying an iterative algorithm to the transformed data until all frequency components without spectral leakage are obtained, and then finding the minimum objective function.

[0013] Furthermore, in order to better densify the detector lines or shot lines, this invention provides a seismic data processing method that reduces the processing scale of the OVT domain. This method also includes an iterative algorithm in which, in each iteration, a Fourier component is selected from the redundancy space. First, the inner product operation is used to find the frequency component with the highest energy. Then, this frequency component is subtracted to obtain updated data. The updated data is then used to find the frequency component with the highest energy again. This process of subtracting frequency components to obtain updated data and using the updated data to find the frequency component with the highest energy is repeated until all frequency components are obtained.

[0014] Furthermore, in order to better densify the detector lines or shot lines, this invention provides a seismic data processing method that reduces the processing scale in the OVT domain, and also includes Fourier reconstruction technology used to transform the seismic data to the frequency-spatial domain.

[0015] To address the aforementioned technical problems, this invention provides a seismic data processing system for reducing the processing scale of the OVT domain, comprising a memory and a processor. The processor executes instructions stored in the memory to implement the aforementioned seismic data processing method for reducing the processing scale of the OVT domain. Attached Figure Description

[0016] Figure 1 This is a flowchart of the seismic data processing method for reducing the processing scale of the OVT domain according to the present invention;

[0017] Figure 2 This is a schematic diagram of the detector line distribution before five-dimensional interpolation in this invention;

[0018] Figure 3 This is a schematic diagram of the detector line distribution after five-dimensional interpolation in this invention;

[0019] Figure 4 This is a schematic diagram of the OVT sheet distribution before five-dimensional interpolation in this invention;

[0020] Figure 5 This is a schematic diagram of the OVT sheet distribution after five-dimensional interpolation according to the present invention;

[0021] Figure 6 This is a schematic diagram of the feed distribution before five-dimensional interpolation in this invention;

[0022] Figure 7 This is a schematic diagram of the gather distribution after five-dimensional interpolation in this invention;

[0023] Figure 8 This is a schematic diagram of the superimposed cross-section before five-dimensional interpolation in this invention;

[0024] Figure 9 This is a schematic diagram of the superimposed cross-section after five-dimensional interpolation of the present invention;

[0025] Figure 10 This is a schematic diagram of the OVT sheet in the first quadrant before cutting, as per the present invention.

[0026] Figure 11 This is a schematic diagram of the OVT sheet in the third quadrant before cutting, as per the present invention.

[0027] Figure 12 This is a schematic diagram of the OVT sheet after cutting the first quadrant OVT sheet according to the present invention;

[0028] Figure 13 This is a schematic diagram of the OVT sheet after cutting the third quadrant OVT sheet according to the present invention;

[0029] Figure 14 This is a schematic diagram of the superimposed cross-section before cutting according to the present invention;

[0030] Figure 15 This is a schematic diagram of the superimposed cross-section after cutting according to the present invention;

[0031] Figure 16 Statistics on the offset range of the OVT sheet before processing in this invention;

[0032] Figure 17 Statistics on the offset range of the OVT sheet after processing according to the present invention;

[0033] Figure 18 This is the pre-stack time offset profile of the OVT domain before processing according to the present invention;

[0034] Figure 19 This is the pre-stack time offset profile of the OVT domain after processing according to the present invention;

[0035] Figure 20 This is the offset profile of the OVT domain after orientation anisotropy correction before processing according to the present invention;

[0036] Figure 21 This is the offset profile after orientation anisotropy correction of the OVT domain processed according to the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and technical effects of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] Examples of seismic data processing methods that reduce the processing scale of the OVT domain:

[0039] This embodiment provides a seismic data processing method for reducing the processing scale in the OVT domain. In this embodiment, the method includes acquiring seismic data; converting the acquired seismic data to the OVT domain; dividing the OVT domain into OVT slices according to shot line spacing and receiver line spacing; for any given OVT slice, acquiring its conjugate OVT slices; performing coordinate interchange on the conjugate OVT slices; superimposing the coordinate-interchangeable conjugate OVT slices onto the original OVT slice; and cutting the superimposed OVT slices along the centerline of the OVT slice and in the direction of the receiver line or shot line to reduce the scale of the OVT slices in the receiver line or shot line direction. The seismic data processing method for reducing the processing scale in the OVT domain according to this embodiment can solve the problem of large processing scale of seismic acquisition data in the OVT domain in the prior art.

[0040] Figure 1 This is a flowchart of the seismic data processing method for reducing the processing scale of the OVT domain according to the present invention. The specific process is as follows:

[0041] Step 1: Obtain earthquake data.

[0042] Specifically, in step one, such as Figure 1 As shown, input the seismic data. The seismic data can be the raw data from seismic acquisition. Raw data typically has relatively regular receiver lines but irregular shot lines.

[0043] Step 2: Based on five-dimensional interpolation technology, densify the detector lines and reduce the processing scale of the OVT shot line direction.

[0044] Specifically, in step two, the seismic data obtained in step one can be densified using a five-dimensional interpolation algorithm to refine the detector lines. The five-dimensional interpolation algorithm can be viewed as solving a large inverse problem. First, the forward problem of the five-dimensional interpolation algorithm can satisfy equation (1): d = T·x (1), where x is the ideally fully sampled five-dimensional data volume, d is the actual recorded wavefield (i.e., the actual data), T is the sampling operator, and "·" indicates multiplication. The ideally fully sampled five-dimensional data volume is mapped to the actual data using the sampling operator. Second, during the actual solution, a forward irregular Fourier transform is performed simultaneously in the five-dimensional space to establish data in the frequency domain. The inverse transform is an underdetermined equation, solving for the minimum objective function J, where the minimum objective function satisfies equation (2): J = ║dT·x║ 2+λ║x║1(2), where ║x║1 is the L1 normal form, λ is the regularization coefficient, λ≥0, and “║║” represents the norm. The L1 normal form can produce relatively sparse solutions and has a certain feature selection capability, which is more effective when solving high-dimensional feature spaces. Therefore, solving the five-dimensional interpolation algorithm is actually solving equation (2) to minimize the minimum objective function J of equation (2). Among them, the selection of the regularization coefficient λ is mainly based on the noise level of the original data. In the actual processing, the regularization coefficient is generally selected as 5%-30% by testing the original data. Thus, the detector line can be better encrypted.

[0045] In step two, the forward irregular Fourier transform performed in five-dimensional space mainly adopts Fourier reconstruction technology. During data processing, the five-dimensional information of the seismic data is fully utilized to densify the detector lines in the shot-detector domain. This can compensate for the problem of insufficient seismic data acquisition to a certain extent. Specifically, the seismic data is transformed into frequency-spatial domain data using Fourier reconstruction operation. Then, for the transformed data, an iterative algorithm is used, and a Fourier component is selected from the redundant space in each iteration. First, the inner product operation is used to find the frequency component with the highest energy. Then, the data of the frequency component with the highest energy is subtracted to obtain the updated data. The updated data is then used to find the next frequency component with the highest energy. This process is repeated (i.e., the steps of subtracting the frequency component with the highest energy to obtain the updated data and using the updated data to find the frequency component with the highest energy) until all frequency components are obtained, thus obtaining all frequency components without spectral leakage. Then, the inverse transform of equation (2) is performed to obtain the regularized seismic data (i.e., the encrypted seismic data). This allows for better encryption of the detector lines. If five-dimensional interpolation is used to densify the detector lines, doubling the density of the detector lines reduces the detector line spacing by half, thus reducing the detector line locality and halving the processing scale of the OVT domain in the shot direction. In this case, conventional three-dimensional data interpolation mainly reconstructs in the common center point domain, and can only process one dimension, either offset or azimuth, and cannot process both offset and azimuth simultaneously. However, five-dimensional data interpolation can simultaneously consider changes in time, space, offset, and azimuth, thereby ensuring that the pre-stack data maintains relative amplitude with both offset and azimuth.

[0046] For the purposes of this embodiment, Figure 2 This is a schematic diagram of the detector line distribution before five-dimensional interpolation in this invention. Figure 3 This is a schematic diagram of the detector line distribution after five-dimensional interpolation according to the present invention. Based on Figure 2 and Figure 3 It can be seen that after five-dimensional interpolation, the detector lines are effectively densified, and the originally irregularly laid detector lines become regular. Figure 4This is a schematic diagram of the OVT sheet distribution before five-dimensional interpolation in this invention. Figure 5 This is a schematic diagram of the OVT sheet distribution after five-dimensional interpolation according to the present invention. Based on Figure 4 and Figure 5 It can be seen that after the detector lines were densified, data was added to areas within the OVT chip that previously lacked data. Therefore, it can be concluded that the acquisition gaps within the original OVT chip were effectively filled. Figure 6 This is a schematic diagram of the track set distribution before five-dimensional interpolation in this invention. Figure 7 This is a schematic diagram of the gather distribution after five-dimensional interpolation in this invention. Based on Figure 6 and Figure 7 It can be seen that the continuity of the gather is improved after the detector line is densified. Figure 8 This is a schematic diagram of the superimposed cross-section before five-dimensional interpolation in this invention. Figure 9 This is a schematic diagram of the superimposed cross-section after five-dimensional interpolation of the present invention. Based on Figure 8 and Figure 9 It can be seen that, Figure 9 The superimposed profile exhibits better line continuity, and the contrast between noise and effective signal is more pronounced. This indicates that the continuity of the superimposed profile is improved, resulting in a higher signal-to-noise ratio.

[0047] In this embodiment, the shot line can be densified using five-dimensional interpolation technology, reducing the processing scale of the OVT domain in the detector line direction. The specific steps for densifying the shot line using five-dimensional interpolation technology can refer to the steps described above for densifying the detector line using five-dimensional interpolation technology.

[0048] Step 3: Divide the OVT (Output Transmission Unit) into segments.

[0049] In step three, the acquired seismic data is converted to the OVT domain, where OVT sheets are divided according to shot line spacing and receiver line spacing. In other words, the OVT domain can be divided into small rectangles based on shot line spacing and receiver line spacing; each small rectangle is an OVT sheet. The OVT domain is a type of cross-shaped domain, and each OVT sheet is a subset of data from that domain. Each OVT sheet includes shot points and receiver points. Shot points are located within a finite range along the shot line. Receiver points are located within a finite range along the receiver line (i.e., the receiver line). A coordinate system is constructed, with the receiver line as the X-axis, the shot line as the Y-axis, and the intersection of the selected receiver line and shot line as the origin of the coordinate system. In step three, the seismic data processed in step two can be converted to the OVT domain.

[0050] Step 4: Based on the principle of interchangeability, the cutting method reduces the processing scale of the OVT detector line direction.

[0051] Specifically, in step four, the cutting method based on the interchangeability principle involves two interchangeable OVT slices (generally, these two interchangeable OVT slices are conjugate OVT slices). First, one OVT slice is rotated 180° around the origin of the coordinate system along the receiver direction. Then, it is overlapped with the other OVT slice. The overlapped OVT slice is then cut along its centerline and in the receiver direction to generate the target OVT slice. In this case, the processing scale of the OVT domain in the receiver direction can be reduced by half. This improves the OVT domain processing effect of seismic data.

[0052] For the purposes of this embodiment, Figure 10 This is a schematic diagram of the OVT sheet before cutting in the first quadrant of the present invention. Figure 11 This is a schematic diagram of the OVT sheet before cutting in the third quadrant of the present invention. Figure 12 This is a schematic diagram of the OVT sheet after cutting the first quadrant OVT sheet according to the present invention. Figure 13 This is a schematic diagram of the OVT sheet after cutting the third quadrant OVT sheet according to the present invention. Figure 14 This is a schematic diagram of the superimposed cross-section before cutting according to the present invention. Figure 15 This is a schematic diagram of the superimposed cross-section after cutting according to the present invention. Figure 10 In the OVT film, the offset distance of each point in the direction from point A1 to point B1 corresponds to the offset distance value of the corresponding grayscale color in the direction from a1 to b1 in the offset distance value bar on the right. Figure 11 In the OVT film, the offset distance of each point in the direction from point A2 to point B2 corresponds to the offset distance value of the corresponding grayscale color in the direction from a2 to b2 in the offset distance value bar on the right. Figure 12 In the OVT film, the offset distance of each point in the direction from point A3 to point B3 corresponds to the offset distance value of the corresponding grayscale color in the direction from a3 to b3 in the offset distance value bar on the right. Figure 13 In the OVT film, the offset distance of each point in the direction from point A4 to point B4 corresponds to the offset distance value of the corresponding grayscale color in the direction from a4 to b4 in the offset distance value bar on the right.

[0053] Taking the reduction of the scale in the detector line direction as an example, the specific implementation process of the cutting method based on the above interchange principle is described in conjunction with the attached diagram. The process is as follows: Figure 10 and Figure 11 The two OVT plates in the middle are two interchangeable conjugate OVT plates. First, Figure 10 and Figure 11The data is copied separately, and the coordinates of the shot and receiver points are interchanged to achieve rotation along the receiver direction. This copied data is then overlaid with the original data. The OVT (Optical Video Recording) data in the third quadrant is discarded, retaining only the OVT data in the first quadrant. This retained OVT data is then separated (cut) along the center line of a rectangle perpendicular to the receiver direction. A new OVT is formed to the left of the center line, and another new OVT is formed to the right of the center line. Figure 12 and Figure 13 The OVT sheet shown is halved in size along the detector line direction. This effectively reduces both the offset range and azimuth range within the newly formed OVT sheet (i.e., the target OVT sheet), thus reducing the size of the OVT sheet along the detector line direction. Based on Figure 14 and Figure 15 It can be seen that the notch on the OVT piece is reduced after cutting. Therefore, cutting can reduce the notch on the OVT piece to a certain extent. The reduction in notch is mainly because the data notch positions of the two interchangeable OVT pieces are inconsistent, and the superimposed cutting has a certain complementary effect.

[0054] In step four, the improvement in the offset range and azimuth range within the cut OVT sheet can be reflected by formula calculation. Specifically, theoretically, the OVT domain processing scale is determined by the shot distance and receiver distance of the seismic data, and its size is twice the shot distance multiplied by twice the receiver distance. That is, the offset range in the receiver direction of an OVT sheet is twice the shot distance, and the offset range in the shot direction is twice the receiver distance. By geometric relationship, the seismic trace offset within an OVT sheet satisfies equation (3): Among them O x O is the offset distance in the direction of the detector line. y The offset distance is in the direction of the shot line, so the offset distance range within a seismic trace of an OVT film satisfies equation (4): Where L s L is the distance between the gun lines. r Given the detector line spacing, the azimuth angle within an OVT plate satisfies equation (5): Therefore, the azimuth range within an OVT plate satisfies equation (6): Where R min R is the minimum offset distance in the direction of the detector line. max S represents the maximum offset in the direction of the detector line. min S is the minimum offset distance in the direction of the shot line. maxThe maximum offset distance is in the shot line direction. In this embodiment, by using a detector line densification technique based on five-dimensional interpolation, the scale of the shot line direction is reduced by half. Then, based on the interchange principle of OVT domain data, the OVT sheet division is optimized by the cutting method, and the scale of the detector line direction is reduced by half. According to equations (4) and (6), it can be calculated that after the OVT sheet scale is reduced, the offset distance and azimuth range of a single OVT sheet are effectively reduced. Thus, the problem of large shot line spacing and receiver line spacing in the original seismic data and large OVT domain processing scale can be effectively improved.

[0055] In this embodiment, it can be seen from the statistical analysis of the offset distance and azimuth range before and after the application of actual data that the offset distance range of the OVT sheet is effectively reduced after the application of the technology to reduce the size of the OVT sheet. Figure 16 This is a statistical analysis of the offset range of the OVT sheet before processing in this invention. Figure 17 This is a statistical analysis of the offset range of the OVT sheet after processing according to the present invention. Figure 16 The average offset range of the OVT film was calculated from the statistics, and the average offset range before processing was 869m. Figure 17 The average offset range of the OVT (Optical Video Recording) images was calculated from the statistical data, resulting in an average offset range of 435m after processing. This demonstrates that by applying techniques to reduce the size of the OVT images, the average offset range decreased from 869m to 435m, effectively reducing the OVT image offset range. Furthermore, before processing, 21% of the OVT images had an azimuth angle range of 0-10°, and 59% had an azimuth angle range of 11-20°. After processing, the percentage of OVT images with an azimuth angle range of 0-10° increased to 78%, while the percentage with an azimuth angle range of 11-20° decreased to 16%, as shown in Table 1.

[0056] Table 1. Statistical table of azimuth range of OVT film before and after treatment.

[0057]

[0058]

[0059] In this embodiment, a cutting method based on the interchangeability principle can be used to cut the stacked OVT sheet along the centerline of the OVT sheet and in the direction of the shot line, thereby reducing the size of the OVT sheet in the shot line direction. The specific steps for reducing the size of the OVT sheet in the shot line direction using the cutting method based on the interchangeability principle can refer to the steps for reducing the size of the OVT sheet in the detector line direction using the cutting method based on the interchangeability principle described above.

[0060] Furthermore, the step of using five-dimensional interpolation to densify the detector lines in step two can also be performed after the OVT sheet division step in step three, or after the OVT sheet division step based on the interchange principle in step four. In this case, the combined application of five-dimensional interpolation technology and the OVT sheet optimization technology based on the division method reduces the OVT domain processing scale by half, reduces the offset and azimuth range within the OVT gather, enhances the consistency of the OVT gather offset and azimuth attributes, and improves the OVT domain processing effect.

[0061] In this embodiment, if the detector lines are encrypted using five-dimensional interpolation technology, the overlapping OVT sheet is cut along the center line of the OVT sheet and along the detector lines using a cutting method based on the interchange principle. If the shot lines are encrypted using five-dimensional interpolation technology, the overlapping OVT sheet is cut along the center line of the OVT sheet and along the shot lines using a cutting method based on the interchange principle.

[0062] In some embodiments, the data encryption techniques for encrypting detector lines or shot lines can include not only five-dimensional interpolation algorithms but also techniques such as trace interpolation and surface element equalization. By using data encryption techniques to encrypt detector lines or shot lines at certain intervals, the detector line spacing or shot line spacing is reduced, thereby reducing the processing scale of the OVT domain in the shot line or detector line direction. In this case, data encryption techniques and OVT sheet optimization techniques based on the cutting method are combined to further reduce the processing scale of the OVT domain.

[0063] Step 5: Subsequent OVT domain processing.

[0064] Specifically, in step five, data is processed in the OVT domain based on the target OVT chip obtained in step four.

[0065] For the purposes of this embodiment, Figure 18 This is the pre-stack time offset profile of the OVT domain before processing according to the present invention. Figure 19 This is the pre-stack time migration profile of the OVT domain after processing according to the present invention. By comparison... Figure 18 and Figure 19 , Figure 19 The contrast between noise and effective signal within the frame is more obvious, the continuity of lines is better, and the imaging of steep structures is clearer. It can be seen that after adopting the method of reducing the OVT domain processing scale in this embodiment, the signal-to-noise ratio and continuity of the offset profile are improved, and the imaging of steep structures is effectively improved. Figure 20 This is the offset profile of the OVT domain after orientation anisotropy correction before processing according to the present invention. Figure 21 This is the offset profile after orientation anisotropy correction in the OVT domain of the present invention, obtained by comparison. Figure 20 and Figure 21 , Figure 21The anisotropy within the frame is better, with fewer spurious breaks. This demonstrates that the azimuth anisotropy is corrected and better eliminated after the method of this invention. The spurious breaks caused by azimuth anisotropy are effectively corrected, resulting in more realistic profile imaging. Therefore, this further proves that the seismic data processing method using the reduced OVT domain processing scale in this embodiment can effectively improve the OVT domain processing effect of seismic data.

[0066] The seismic data processing method for reducing the processing scale of the OVT domain, based on this embodiment, employs a receiver line densification technique based on five-dimensional interpolation. The receiver lines are densified by a factor of one, reducing the processing scale in the shot line direction by half. Then, after OVT sheet partitioning, based on the interchangeability principle of OVT domain data, a cutting method is used to optimize the OVT sheets, further reducing the OVT domain processing scale in the receiver line direction by half, thus ultimately achieving the goal of reducing the OVT sheet processing scale by half. In this case, considering the relatively regular receiver lines and irregular shot lines in field seismic data, the five-dimensional interpolation technique using only densified receiver lines provides higher fidelity than the conventional five-dimensional interpolation method that interpolates both receiver and shot lines. The cutting method for OVT sheet optimization based on the interchangeability principle fully utilizes the interchangeability of OVT data, without altering the original data, but rather allowing different OVT sheet data to complement each other, thereby better protecting the data characteristics in the original data. By reducing the OVT sheet scale, the range of offset and azimuth within the OVT gather is reduced, enhancing the consistency of offset and azimuth within the OVT gather, resulting in a significant improvement in the OVT domain processing effect.

[0067] Examples of seismic data processing systems that reduce the processing scale of the OVT domain:

[0068] This embodiment discloses a seismic data processing system for reducing the OVT domain processing scale. The seismic data processing system for reducing the OVT domain processing scale can be simply referred to as a seismic data processing system. Through the seismic data processing system for reducing the OVT domain processing scale of this embodiment, a seismic data processing method for reducing the OVT domain processing scale described in the method embodiment of this invention can be implemented.

[0069] In this embodiment, the seismic data processing system for reducing the OVT domain processing scale includes a processor and a memory. The processor executes instructions stored in the memory to implement the seismic data processing method for reducing the OVT domain processing scale in the method embodiment of the present invention. This seismic data processing method for reducing the OVT domain processing scale has been described in detail in the above method embodiment. Those skilled in the art can generate corresponding computer instructions based on this seismic data processing method for reducing the OVT domain processing scale to obtain the seismic data processing system for reducing the OVT domain processing scale, which will not be elaborated further here. The memory stores the computer instructions generated according to the seismic data processing method for reducing the OVT domain processing scale.

[0070] The seismic data processing system based on this embodiment, which reduces the processing scale of the OVT domain, can solve the problem of improving the OVT domain processing effect when the shot line spacing and receiver line spacing of the seismic acquisition data are large in the prior art.

Claims

1. A seismic data processing method for reducing the processing scale in the OVT domain, characterized in that, include: 1) Seismic data is acquired, and the acquired seismic data is encrypted at certain intervals using data encryption techniques to reduce the scale of the OVT domain in the shot or receiver directions. The data encryption techniques include one of five-dimensional interpolation, trace interpolation, or surface element equalization. The five-dimensional interpolation algorithm transforms the seismic data into frequency-spatial domain data. Then, an iterative algorithm is applied to the transformed data until all frequency components without spectral leakage are obtained. Finally, the minimum objective function is calculated, which satisfies the following equation: Where J represents the minimum objective function, d is the actual recorded wave field, T is the sampling operator, x is the ideal fully sampled five-dimensional data volume, λ is the regularization coefficient, λ≥0, and ║x║1 is the L1 norm; In the iterative algorithm, each iteration selects a Fourier component from the redundant space. First, the inner product operation is used to find the frequency component with the highest energy. Then, the frequency component is subtracted to obtain the updated data. The updated data is used to find the frequency component with the highest energy again. The steps of subtracting the frequency component to obtain the updated data and using the updated data to find the frequency component with the highest energy are repeated until all frequency components are obtained. 2) Convert the acquired seismic data to the OVT domain, and divide the OVT sheets in the OVT domain according to the shot distance and receiver distance; 3) For any OVT sheet, obtain its conjugate OVT sheet, perform coordinate interchange on the conjugate OVT sheet, and superimpose the coordinate interchanged conjugate OVT sheet onto the OVT sheet. Cut the superimposed OVT sheet along the center line of the OVT sheet and in the direction of the detector line or the shot line to reduce the size of the OVT sheet in the direction of the detector line or the shot line.

2. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 1, characterized in that, Each OVT sheet includes a shot point and a receiver point. The shot point is located within a finite range along the shot line, and the receiver point is located within a finite range along the receiver line.

3. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 1, characterized in that, After cutting, the offset distance of an OVT plate in the detector line direction is twice the shot distance, and the offset distance in the shot line direction is twice the detector line distance.

4. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 3, characterized in that, The regularization coefficients are selected based on the noise level of the original data.

5. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 3, characterized in that, The regularization coefficient is selected as 5%-30%.

6. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 1, characterized in that, The offset range within the seismic trace of a cut OVT slice satisfies: in This is the distance between the gun lines. This refers to the detector line spacing.

7. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 1, characterized in that, After cutting, the azimuth range within one OVT piece satisfies: in This is the minimum offset distance in the direction of the detector line. The maximum offset distance in the direction of the detector line. This is the minimum offset distance in the direction of the shot line. This represents the maximum offset distance in the direction of the shot line.

8. The seismic data processing method for reducing the processing scale of the OVT domain according to claim 6, characterized in that, The Fourier reconstruction technique is used to transform seismic data into the frequency-spatial domain.

9. A seismic data processing system for reducing the processing scale in the OVT domain, characterized in that, include: A memory and a processor, the processor being configured to execute instructions stored in the memory to implement the seismic data processing method for reducing the processing scale of the OVT domain as described in any one of claims 1-8.

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